Question

A fabric filter is to be constructed using bags that are 0.1 m in diameter and 5.0 m long. The bag house is to receive 5 m³/s of air. Filtering velocity is 2.0 m/min. Determine the minimum number of bags required for continuous removal of particulate matter.
1. 96
2. 106
3. 78
4. 88

Answer 1

Correct Answer - Option 1 : 96

Concept:

The minimum number of bags required for continuous removal of particulate matter (n) = \(\frac{bag\: house\: to\: receive\: air}{surface\: area\: of fabric \: filter\: ×\:filtering\:velocity}\)

Calculation:

Given:

Bag house is to receive air = 5 m3/s, Surface area of fabric filter = surface area of cylinder (s) = 2πrl + πr² 

r = radius of cylinder = (0.1/2) = 0.05 m, l = lenght of cyliner = 5 m.

Filtering velocity = 2.0 m/min = 2/60 m/s = 0.033 m/s.

s = (2 × π × 0.05 × 5) + (π × 0.05²) = 1.578 m²

Now, we know that

(n) = \(\frac{bag\: house\: to\: receive\: air}{surface\: area\: of fabric \: filter\: ×\:filtering\:velocity}\)

n = \(\frac{5}{1.578 ×\:0.033}\)

n = 96